1. Field of the Invention
The present invention relates to apparatus for performing a plurality of size reducing actions including impact fragmentation, cutting and shearing by means of an impact rotor mounted for rotation within a reduction chamber. More particularly, the present invention relates to the impact striker assembly carried by the lobes of a rotor which cooperate with a stationary anvil or wear surface and a grate to perform cutting and shearing action of the type described in U.S. Pat. No. 5,150,844 to McKie, especially the embodiment of FIG. 8 therein, the disclosure of which is included herein by reference.
2. Description of the Prior Art
Typical prior art heavy duty material reduction apparatus utilizing impact rotors of the type under consideration are disclosed in U.S. Pat. No. 4,151,959 to Deister and U.S. Pat. No. 5,150,844 to McKie. These patents are illustrative of the prior art utilizing either a radially attached, axially or helically extending cutter bar or striker plate. The McKie patent, for instance, illustrates a cutter bar extending axially on the surface of a rotating drum for direct impact cutting in cooperation with an anvil, hardened wear surface or grating. The cutter bar is also shown with multiple removable striker plates mounted thereon for contact with an anvil or other surface. The Deister patent illustrates still another type of impact rotor comprised of a series of rotary segments with offset, radially extending lobes for mounting removable striker plates. In both types of apparatus, the cutter bar or an attached striker plate includes a leading hardened cutting edge subject to severe wear and deterioration because of the high impact loads experienced during material processing. The cutter bar or striker plates may be symmetrical so as to include two cutting edges with the striker plate or cutter bar being capable of reversal or turning to utilize a second cutter edge. Whether the cutter bar or striker plate is unitary or segmented, it is necessary to completely remove the plate or bar assembly from the rotor in order to replace a cutting edge or to reverse the position of the cutter bar or striker plate. In heavy duty rotary hogs this operation is not only expensive and time consuming but requires access to the massive rotor element under hazardous working conditions.
Although other types of cutter bars striker plates and removable cutting edges have been proposed, either the entire striker plate or cutter must be removed for reworking or the complexity of the attachment means for removable cutting elements precludes their use in heavy duty crushers and rotary hogs. For instance, there is a need for replaceable cutting tools or bits which may be removed by easily accessible bolts without requiring lateral movement of the parts. The cutting tool or bit and striker plate must at the same time be configured for simplicity and maximum ruggedness in order to withstand the extremely high impact pressures without fracturing. The attaching means must be arranged so as not to interfere with the material processing and require no particular special skills to manipulate.